It’s often said that we live in an era that prizes speed and brevity above all else. There’s long been fast food, but now there’s fast fashion, too. Why take the time to phone someone when an email will take less of your time? Why send an email when a text message would be quicker?

For that matter, why take the time to type the words “I know, right?” or “Just kidding” when you can just type “IKR?” and “JK”?

Attention spans may be shrinking to the blink of an eye or two, but there are still some of us who would rather read a fat Victorian novel than plow through a day’s tweets. (Shameful, but true: I am still not on Twitter. It was hours – hours! — before I learned of the sad demise of “Brangelina.”)

And while I am never brokenhearted to learn that a play I’m going to see runs a tight 90 minutes, some of the most memorable theatergoing experiences of my life have also been among the longest. I am thinking not just of “The Flick,” Annie Baker’s Pulitzer Prize-winning play that clocked in at more than three hours, but of productions that can take up a full day’s span.

I saw all of the great Irish writer J. M. Synge’s plays, presented by the Druid Theater, separately on three nights in Dublin several years ago. Then, at the urging of the director, Garry Hynes, I saw them again on a single day in Dublin. Ms. Hynes felt that the immersion in Synge’s world that came from watching them back to back was far more illuminating, and moving, than seeing the plays in discrete chunks.

What good long-form theater can do so well is draw us out from the picayune distractions of daily life — the email inbox inevitably filling up, the bleeps from our phones — to give us a wider and deeper view of our experience, or, more significantly, someone else’s. Time slows down, the nagging irritations of our personal lives slip away, and we enter into a world imagined by an artist or artists that holds us captive for a while.

We emerge into the real world a little bit disoriented — and, yes, probably tired and ready for bed — but with a crucial sense of having entered another realm for a while, lived there, and learned something from it.

Of course, not all of my long-form theatrical journeys have left me with a smile on my face. I have immense respect for the director-writer-actor Robert Lepage, but his nine-hour “Lipsynch,” presented at the Brooklyn Academy of Music in 2009, was a meandering, maundering meditation on language and speech that ultimately left me with just one word ringing in my head after it concluded: “Taxi!”

But by a happy coincidence, two of the most adventurous, inspired and, yes, lengthy works of theater I’ve seen are coming to a conclusion in New York at roughly the same time. Both reward the time spent, spectacularly.

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Time-lapse video of Mr. Mac getting into costume for the 1836-1866 portion of his "24-Decade History of Popular Music," a look he calls a "re-imagining of a classic American delicacy, a product of its time."Published OnSept. 13, 2016

For the next couple of weeks, Taylor Mac performs his long-gestating magnum opus (or let’s be optimistic and call it his first magnum opus), “A 24-Decade History of Popular Music,” in three-hour installments at St. Ann’s Warehouse in Brooklyn. They continue through Oct. 3, culminating in a marathon performance on Oct. 8 at noon that lasts a staggering 24 hours. Bring your sleeping bag if you want to catnap.

If you aren’t holding tickets for Mr. Mac’s performance this Saturday, you could watch the final three installments of the similarly long-aborning “Life and Times,” from the experimental company Nature Theater of Oklahoma, which are being screened (yes, screened — more on that later) at Anthology Film Archives as part of the French Institute Alliance Française’s Crossing the Line Festival.

With these concluding segments, the project will have stretched to 16 hours or so — shy of Mr. Mac’s endeavor, but pretty lengthy by any standards nonetheless. The final three parts take up about four and a half hours.

Neither of these events fall squarely into the category of theater. Mr. Mac’s production is a hyperextended song cycle blended liberally with inspired patter, history viewed through a queer prism, elaborate audience-involving theatrical gambits and the occasional guest star. I have seen half of the production, covering the years 1776 through 1836, and the years 1896 through 1956 (which I reviewed last year), and can attest to its glittering uniqueness: the most spectacular drag act imaginable, combined with superb musicianship and generous doses of progressive gender politics.

The first four “episodes” of “Life and Times,” conceived and directed by Pavol Liska and Kelly Copper, were presented at the Public Theater in 2013, in collaboration with Soho Rep. Although radically strange, even by the standards of experimental theater, they took place onstage, with live actors and musicians present. But the next installments — Episodes 4.5 and 5 — left theater entirely behind. The first was a short animated film, the second a book loosely inspired by early medieval illuminated manuscripts.

The final three episodes (No. 6 was performed only in Europe) are entirely filmed, although, in keeping with the dizzying, dazzling variety that exemplify the project, each has a distinct style. Episode 7 departs most startlingly from what has come before in that the voice that we had been hearing (or reading), that of the performer Kristin Worrall, is entirely absent.

The previous episodes were drawn from recorded telephone conversations with Ms. Worrall, using her exact wording. Liberally sprinkling familiar verbal tics like “like” and “um” throughout her chatter, not to mention fractured sentences and digressions, she unfolded the not particularly remarkable story of her youth and teenage years, in often hilariously granular detail.

In Episode 7, a similar allegiance to the quirky poetry of human speech trapped in amber remains, the voices we hear are those of Ms. Worrall’s friends and family, not her own. (She does appear in the movie, as herself.) The story of Ms. Worrall’s life picks up as she’s adrift, attending college, taking dead-end jobs and generally experiencing the kind of malaise that descends upon artistically inclined but far from driven young people as they negotiate the first years of adulthood.

Perhaps reflecting this sense of life flattening out after the hormonal turbulence of adolescence, the movie is filmed almost entirely in black and white. The visual style, however, is striking: Scenes are filmed against hazy backdrops of other films; a short introductory segment imitates an old-style newsreel, replete with scratches on the film. Only in the last moments does the movie transform into color.

The next, considerably shorter episode, is made entirely in color — but it’s also entirely sung. (All three episodes have English subtitles.) A filmed opera, in effect, the movie zips between various locations in and around New York and returns Ms. Worrall’s voice to the fore.

It climaxes, movingly, in Ms. Worrall’s reflections on her experience during the events of Sept. 11, 2001, as we watch the actors singing as they stride across the Brooklyn Bridge, with the new 1 World Trade Center building in the background.

Episode 9, meanwhile, is also sung, but it’s an extended spoof of a rap video. This last leg of the journey felt like a letdown — almost as if Mr. Liska and Ms. Copper had run out of inspiration — but it hardly diminished my admiration for the project as a whole.

In “Life and Times,” they and their collaborators turn a regular life into an aesthetic saga. The process itself became a funny and moving illustration of the idea that even as we change and evolve, something of us — in this case represented by the specific voice of Ms. Worrall — remains intact. Life is both ever-various and surprising, and, at the same time, one long uninterrupted (and, admit it, sometimes awfully boring) conversation with ourselves.